log: move CreateNewBlock() log line behind a new mining category #36336

pull ismaelsadeeq wants to merge 2 commits into bitcoin:master from ismaelsadeeq:09-2026-mining-log-category changing 4 files +11 −1

ismaelsadeeq commented at 3:27 PM on September 25, 2026: member

Fixes #36334

The "CreateNewBlock(): block weight: ..." line was logged unconditionally and could not be turned off, filling the debug log when block templates are built frequently.

Move it behind a new "mining" logging category, enabled with -debug=mining.
DrahtBot added the label Utils/log/libs on Sep 25, 2026
DrahtBot commented at 3:27 PM on September 25, 2026: contributor



The following sections might be updated with supplementary metadata relevant to reviewers and maintainers.



Code Coverage & Benchmarks

For details see: https://corecheck.dev/bitcoin/bitcoin/pulls/36336.



Reviews

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Type Reviewers

ACK w0xlt, l0rinc, achow101

Concept ACK sedited

Stale ACK willcl-ark, Sjors

If your review is incorrectly listed, please copy-paste <code></code> into the comment that the bot should ignore.
sedited commented at 3:32 PM on September 25, 2026: contributor

Concept ACK
in test/functional/mining_basic.py:427 in e7d91c2034 outdated
```
 423 | @@ -424,6 +424,12 @@ def test_height_in_locktime(self):
 424 |          assert_equal(block["tx"][0]["locktime"], block["height"] - 1)
 425 |          assert_equal(block["tx"][0]["vin"][0]["sequence"], MAX_SEQUENCE_NONFINAL)
 426 |  
 427 | +    def test_mining_log_category(self):
```
l0rinc commented at 6:51 PM on September 25, 2026:

I don't think this is useful, it's not the same abstraction level as test_murch_zawy_mintime and test_pruning and test_height_in_locktime

ismaelsadeeq commented at 9:48 AM on September 28, 2026:

Not sure what the suggestion is here, based on the current state of the PR, the test tests a feature added by the PR and fails after running without the production code. AFAICT, it belongs in that file because tests of the same caliber are there as well, like blockmintxfee_parameter etc.

l0rinc commented at 5:14 PM on September 28, 2026:

A manual reproducer could be simpler, tests also have a maintenance burden, this seems like a one-off change that we don't need to test on every build, just on the transition (i.e. this PR). Not a blocker.

stickies-v commented at 12:33 PM on September 29, 2026:

this seems like a one-off change that we don't need to test on every build, just on the transition

I agree. These kinds of tests feel incredibly noisy to me, don't add anything meaningful, and are much costlier to remove than they are to add.

Sjors commented at 4:32 PM on September 29, 2026:

I guess the question is whether we want to have a functional test for every log message?

ismaelsadeeq commented at 5:32 PM on September 29, 2026:

I removed the tests. Thanks for the review.
in src/logging/categories.h:48 in e7d91c2034 outdated
```
  44 | @@ -45,6 +45,7 @@ enum LogFlags : CategoryMask {
  45 |      TXPACKAGES = (CategoryMask{1} << 27),
  46 |      KERNEL = (CategoryMask{1} << 28),
  47 |      PRIVBROADCAST = (CategoryMask{1} << 29),
  48 | +    MINING = (CategoryMask{1} << 30),
```
l0rinc commented at 6:57 PM on September 25, 2026:

Adding a whole new log category for a single debug line seems excessive, could we put this behind an existing close-enough category instead? Mempool seems like the natural home: this line is reporting what got pulled from the mempool into the template, and anyone debugging fee/tx-selection issues already runs -debug=mempool. We can add a new category when the examples demonstrate a need.

ismaelsadeeq commented at 9:52 AM on September 28, 2026:

This was discussed in the issue #36334 in comparison with other alternatives, which aren't ideal. I think using the mempool category for mining code here is incorrect.

New logs will likely be added in the future; see project #33758.

Sjors commented at 10:09 AM on September 28, 2026:

I think having a dedicated mining log category makes sense. Putting this message in the mempool category would be confusing for miners, and also impractical because mempool is extremely noisy.

l0rinc commented at 5:14 PM on September 28, 2026:

If others are okay with it since we expect to have more coming, I don't mind, please resolve
l0rinc changes_requested
l0rinc commented at 6:58 PM on September 25, 2026: contributor

Concept ACK, but approach seems excessive
ismaelsadeeq commented at 9:52 AM on September 28, 2026: member

cc @Sjors @willcl-ark @w0xlt
Sjors commented at 10:11 AM on September 28, 2026: member

Needs a release note that recommends getblocktemplate and Mining IPC users enable this category.
ismaelsadeeq force-pushed on Sep 28, 2026
ismaelsadeeq commented at 11:32 AM on September 28, 2026: member

Needs a release note that recommends getblocktemplate and Mining IPC users enable this category.

Done.
willcl-ark commented at 1:11 PM on September 28, 2026: member

Concept ACK

I did a search of github and google for "CreateNewBlock(): block weight: to try and find any other projects which bight be relying on parsing this log line, but didn't find anything noteworthy (except someone trying to suppress it).

I think adding a new category seems fine and on balance probably appropriate here; I get why it might appear overkill too though (it's only one log line), but I agree it doesn't really fit into mempool, validation, estimatefee or any other current category neatly.

Not strong opinion on the value of the test.
willcl-ark approved
willcl-ark commented at 1:16 PM on September 28, 2026: member

ACK 7a2c89e1923682e81184b7908a793033c3bd3312

happy with this change both with or without test.
DrahtBot requested review from l0rinc on Sep 28, 2026
DrahtBot requested review from sedited on Sep 28, 2026
Sjors commented at 1:42 PM on September 28, 2026: member

ACK 7a2c89e1923682e81184b7908a793033c3bd3312
l0rinc approved
l0rinc commented at 5:16 PM on September 28, 2026: contributor

ACK 7a2c89e1923682e81184b7908a793033c3bd3312

While I don't see why a debug log line needs release notes and new category and tests, other reviewers seem to agree with it so I won't block
log: move CreateNewBlock() log line behind a new mining category 54b8795121
doc: add release notes df3008418c
ismaelsadeeq force-pushed on Sep 29, 2026
w0xlt commented at 6:21 PM on September 29, 2026: contributor

ACK df3008418c20f7eb23736b893c2b997db93ce433
DrahtBot requested review from willcl-ark on Sep 29, 2026
DrahtBot requested review from Sjors on Sep 29, 2026
DrahtBot requested review from l0rinc on Sep 29, 2026
l0rinc commented at 7:47 PM on September 29, 2026: contributor

diff and code review reACK df3008418c20f7eb23736b893c2b997db93ce433
achow101 commented at 9:18 PM on September 29, 2026: member

ACK df3008418c20f7eb23736b893c2b997db93ce433
achow101 merged this on Sep 29, 2026
achow101 closed this on Sep 29, 2026
ismaelsadeeq deleted the branch on Sep 30, 2026
fanquake commented at 9:31 AM on September 30, 2026: member

Backported 54b8795121d3081019befd8a2bc70adcd06fcb65 to 32.x in #36300. Any relevant release notes can be added directly to the wiki.
fanquake referenced this in commit 18765f6734 on Sep 30, 2026
fanquake referenced this in commit 5ac9f35735 on Oct 1, 2026
ismaelsadeeq commented at 4:28 PM on October 1, 2026: member

Backported 54b8795 to 32.x in #36300. Any relevant release notes can be added directly to the wiki.

Done, with respect to this and #36365. @janb84, I think the testing guide should also be adjusted?